recommend a continuous duty link radio

eboe · Post by **eboe** » Fri Jan 20, 2006 9:09 am

i'm looking for a current-production motorola radio that can handle a continuous duty link for a voting system with status tone. it'll be in the 450-460 Mhz range with maybe 5-10 watts on a yagi. what models would you guys recommend for this?

thanks

eboe · Post by **eboe** » Fri Jan 20, 2006 12:32 pm

...i was thinking, would an MTR2000 be a good choice for this? i was probably going to use an MTR2000[RX Only] on the receive side anyway, so if i just got a regular repeater/base version i could do the RX & TX in one chassis. question still remains though, would it hold up to a 100% duty cycle??

thanks

Post by **wavetar** » Fri Jan 20, 2006 12:57 pm

The MTR2000 repeater is continuous duty rated for 30, 40, & 100watts, depending on the PA it's ordered with, so 10 watts will be no problem. It's used heavily in analog trunking systems with continuous control channels & high duty cycle voice channels, so it's built to handle that sort of thing & shrug it off.

Todd

Alan · Post by **Alan** » Fri Jan 20, 2006 2:30 pm

We have a 100 watt MTR2000 that has been keyed on at 60 watts for the last 6 years.
It is a taxi data TX. It is still pumping out the 60 watts today (touch wood).

FMROB · Post by **FMROB** » Fri Jan 20, 2006 5:09 pm

Get a MSF5000 if you want a great, true, continuous duty radio.

That is of course not wanting to spend I would say 7K+ on an MTR2000.

The average computer programmable, clean, used MSF is going for about $500-1,000.

eboe · Post by **eboe** » Fri Jan 20, 2006 7:58 pm

well that's the thing. this is going to have to be purchased as new equipment on a state contract bid from a motorola dealer. so used stuff is out of the question. $7g's for the MTR? yikes. ...thought they were a little cheaper than that. :/

Post by **wavetar** » Sat Jan 21, 2006 5:18 am

The 40-watt UHF R1225 repeater is rated for continuous duty at 25-watts, so 10 watts should be a joke for it. You could purchase two of them for less than the cost of a single MTR2000.

And I know someone is going to chime in with the Kenwood TKR850...but I'm assuming you wanted to keep it Motorola.

Todd

FMROB · Post by **FMROB** » Sat Jan 21, 2006 7:12 am

I appoligize, I didn't fully read your first post. You said you wanted "current-production". The MSF is OOP.

Sorry....

Last I checked the MTR based as a repeater was no cheaper than $6k, I could be wrong.

PRR · Post by **PRR** » Sat Jan 21, 2006 7:50 am

If all that is required is 10 watts, I'll second Wavetar's suggestion of the r1225. We have a fleet that, with forced air cooling, have run in continuous transmit at 30 watts for up to two week periods many, many times. This is on top of the fact that the units have their power cycled between transmit stints in order to be shipped around the country on a regular basis. They have proven most reliable.

And Humhead is about to spend a week with two of them (again) and he has yet to complain - At least not about the r1225's.

Henry

Post by **HumHead** » Sat Jan 21, 2006 9:35 am

While I'm a big fan of the MTR2000, dollar for dollar, it is hard to argue with the R1225s for low power continuous operation.

I'll save my complaining for when you call to compare notes on the weather.

chartofmaryland · Post by **chartofmaryland** » Sat Jan 21, 2006 11:59 am

Your not going to find mobiles that can take continous Tx made after 2001. I've found failures in turning down 25 watt mobiles and running them continously in Tx. Some models that failed are the Sm50, M1225, CM300, CDM750. Even with fans on the PA's and them only putting out say 10 watts, 5 in other cases, they all just didn't like the continous Tx. I found alot that the antenna switching cuircut just failed by opening up.

There are some 2001 and older that work fine. One being the Low power Maxtrac. Look for model numbers that start with, M04 the "0" representing 0-5 watts. Perfect for running a link and includes PL and my favorite for links, DPL. These are off shelve RSS programmable, reliable link radios. Turn the power as low as the link can stand it. If you start to lose signal on the link look to up the gain on the antenna system before turning up the power. Finally, put a fan on the PA and let it go. That maxtrac can Tx for a VERY ( years? ) long time with 2 watts, output and a fan on the PA. Got alot of reliable years out of the ones I've seen in Link / Voting / Status Tone Voting systems. And even if it fails you can fix it over having to try and magnify the problem ( SMD transistor or the like ) component that went bad in the back of you CDM750.

The other non current model is the Maxar. The whole radio has parts that have to be modded, but when complete, they are the most stable link Tx and Rx platforms still around. The "Micor" of link radio's. These are very good for keeping up on your technical abilites if you are into modifying and repairing radios past programming them. Don't be scared of the fact they are crystal radios, that helps in making them better for linking.

For the price the MTR2k is lot of the time out of the picture but will deffinatly work for a continous duty Txer.

Hope this gives some direction.

CoM

tvsjr · Post by **tvsjr** » Sat Jan 21, 2006 12:48 pm

wavetar wrote:And I know someone is going to chime in with the Kenwood TKR850...but I'm assuming you wanted to keep it Motorola.

Being a tad sarcastic, aren't we, Todd? Just because Kenwood produces a radio capable of continuous duty TX at 25 watts that you can pick up for $1K from your local dealer and Motorola doesn't turn out anything even in the same ballpark doesn't mean you have to get snitty.

Post by **wavetar** » Sat Jan 21, 2006 1:56 pm

tvsjr wrote:
wavetar wrote:And I know someone is going to chime in with the Kenwood TKR850...but I'm assuming you wanted to keep it Motorola.
Being a tad sarcastic, aren't we, Todd? Just because Kenwood produces a radio capable of continuous duty TX at 25 watts that you can pick up for $1K from your local dealer and Motorola doesn't turn out anything even in the same ballpark doesn't mean you have to get snitty.

Not at all, it's a compliment to Kenwood that they have such a fine repeater in that price scale. Just figured I'd mention it before you did

Todd

tvsjr · Post by **tvsjr** » Sat Jan 21, 2006 8:55 pm

wavetar wrote:Just figured I'd mention it before you did

Mee? Nah. Personally, for our link radios, we use old GE MVPs and Mastr Exec IIs (ham network with around 55 repeater sites throughout the state). Which, if anyone has any laying around, I'd love to get my hands on!

Moto is missing the boat by not countering the TKR-x50 with something at least approaching comparable.

Post by **wavetar** » Sun Jan 22, 2006 5:22 am

Other than a loose front end, I feel the R1225 does at least approach it...same continuous duty spec at 25-watts, single chassis design (it's not 2 back-to-back radios as some seem to think), easy to interface and is 'program & play'. We've sold a lot of them & they just plain work. My only real beef with them is the lack of a low-split 403-433 UHF model...that's why we had to go with TKR's for one system.

Todd

PRR · Post by **PRR** » Sun Jan 22, 2006 10:50 am

Other than a loose front end, I feel the R1225 does at least approach it...

True, but a $250 - $350 preselector or notch pass filter takes care of most of the front end selectivity shortcomings. Still a bargain in non-critical, non super hostile RF environments, IMHO.

Henry

Dan562 · Post by **Dan562** » Sun Jan 22, 2006 2:22 pm

Eboe,

If you intend to use MTR2000 repeaters out at your remote receiver sites for Satellite Receiving and then RF Linking back to the Analog Voting comparator. How do your intend to interface the 2175 Hz Status Tone Link output from the receiver's Wire Line back into the transmitter (configured for Flat Audio Response) and provide the COR (Aux I/O Module) from the receiver? Don't forget you'll need a seperate frequency for each Link Transmitter and Receiver Link. And a seperate MTR2000 Satellite Receiver for each Link Input to the Analog comparator.

You may want to consider /\/\otorola's Canopy Product Line for Linking the Satellite Receivers back to the Analog comparator. Or using Digital Microwave equipment instead of Telco T1 wire lines.

Post by **/\/\y 2 cents** » Sun Jan 22, 2006 3:25 pm

May I ask how this voting system is going to be carrying the return path audio?

Steve

RADIOMAN2002 · Post by **RADIOMAN2002** » Mon Jan 23, 2006 6:10 pm

I think you are going about the voting the wrong way. I have 2 voting systems using Motorola Spec-Tac comparators and I don't send the stat tone over the link. I merely use simple repeaters, with flat TX audio. The repeater, uses some old Micor repeater cards, that give the RXer some thing to key the link Tx with. (You can use anything to do that but I recommend a 2 sec link TX delay to prevent chattering on a weak RX signal) I also route the incoming PL tone into the link TXer so there is no extra hang on the comparator. Now the Spec-Tac goes at the repeater site where you bring in all the link RXers into the comparator and do your voting there, as if it were comming in on a phone line. One thing though use all the same recievers and transmitters, audio cards etc, so you don't end up with an imbalance in audio frequency repsonce, it will drive the Spec-Tac crazy.

jim · Post by **jim** » Fri Jan 27, 2006 6:09 am

Why not just a "cheaper" 900 MHz spread-spectrum link? It's still cheaper than an MTR2K.

nmfire10 · Post by **nmfire10** » Fri Jan 27, 2006 8:11 am

wavetar wrote: And I know someone is going to chime in with the Kenwood TKR850...but I'm assuming you wanted to keep it Motorola.

Todd

I'm with him!

eboe · Post by **eboe** » Fri Jan 27, 2006 11:12 am

RADIOMAN2002 wrote:I think you are going about the voting the wrong way....

you know what? i agree with you! i don't want to do it this way either, but it seems like every time i recommend the right way to do something, i'm asked for a different way or a cheaper way. I'd like to use MTR receivers, telco leased-lines, digi-tac comparator and call it a day.

the problem lies in the fact that we won't "own" the infrastructure if we use leased-lines. not only will we have a recurring fee from the lease, but we'll be dependant on someone elses system. I kinda see their point, but from what i've learned, leased lines are relatively dependable and isolated from the rest of the telco switching and thereby not affected by hi-volume telephone traffic. i was told by our regional telco rep that pretty much the only things that could take down the leased line service are physical breaks in the line or if the switching hub blew up which is basically a physical break in the line.

another problem is with the location of our repeater for that channel. the building does not belong to us and we are having issues with regards to getting approval to change anything that we already have in place there. normally i'd say screw em', but it's the best building in town to transmit from.

my plan is to have the voting receivers on several of our buildings in town and also one at the repeater site [not owned by us]. run all the telco lines down to a centrally located building owned by us where the comparator is. then a single telco line can return to the repeater building with the voted audio.

basically, from the building that doesn't belong to us, i'd need one telco out, one telco in. in the rack at i'd need to add an MTR receiver. i bet the antenna could even be a quarter-wave magnet mount on the repeater cabinet. we've had a similar antenna on the cabinet for a cross-band system and it's worked fine from up close which is all a voting receiver needs to do.

so that's how "I" want to do it. any better?

my way doesn't use RF links so i wouldn't need any new FCC licenses or hardware for the link. that makes it a much simpler system and i've always been a big fan of the KISS theory. plus i'm guessing that the telco audio will be better than another RF path, correct?

edited to add: i almost forgot.. i would also like to have the repeater configured for an "in-cabinet" repeat in case the whole voting/comparator system took a dump for whatever reason.

Post by **xmo** » Fri Jan 27, 2006 3:41 pm

Using phone lines certainly simplifies your system design - after all - that is the way Motorola designed the product to be used. Be aware that if you use Spectra-Tac and if you have a voting receiver co-located with the voter, you should have a 'roofing' filter module installed in the comparator for that receiver's signal quality module to equalize the local path frequency response to match the response of the leased lines, thereby avoiding problems with the system not voting 'logically'.

You might not need to add another MTR receiver at the repeater site, depending on what type of station the repeater itself is. If the repeater's receiver is capable of being a voting receiver [e.g. option C269 on Micor/MSR2000] then one receiver suffices.

Also you don't need two phone lines from the comparator site to the repeater site - just specify that line as a 4-wire circuit. That should cost about the same as a 2-wire circuit. Voting receiver audio goes one way and audio to the transmitter goes the other.

BTW, the MTR2000 cannot do fall-back in-cabinet repeat. The thieves at Motorola have decided that feature belongs in their"high tier" product line [i.e. Quantar].

kb4mdz · Post by **kb4mdz** » Fri Jan 27, 2006 9:43 pm

Leased lines are a boon & a bane; My experience has been that there are very few telco techs who understand leased lines, so it's common to chase around for a week or so after you are told they are "installed"; generally, I have found that they're installed, but then nobody thinks to "provision" them, (set the levels of the terminating packages) or if they do remember, just do it on the telco side, not the customer side.

Other thing is, when you have to call in a circuit, most calltakers and most techs, again, don't know anything about leased lines. So you might chase your tail and telco's tail for a day or two before you get it resolved. I had one circuit once that went into 3 weeks of passing the buck back-n-forth. Call in, & one or two days later I get a response. "Set levels, all OK." BS. Still dead at the other end. Call in again. "Swapped cards in CO, set levels." Nope, still dead. Call in again. "No trouble found; checks good" Yeah, right. Finally had to meet not one, but two old-time, brain-atrophied, over-time sucking, union-scale-overpaid flunkies at the originating end, during the evening, and repeat multiple times what was happening. They finally found an open side of the pair at the pedestal on the street corner.

Other than that, they can be pretty reliable......

If you go leased lines, get a good phone number of the account's business manager inside the telco.

Another thing about a good voter system, if you have a failure of one or more circuits, the voter can indicate what failed, and if you tie that into a monitoring system like Davicom or Pro-Tek, you can get paged out when a failure happens.

Plan carefully. And stand your ground for an effective system, not just one that will be cheap.

"It's the stingey man who ends up paying the most"

Chuk G.

eboe wrote:
RADIOMAN2002 wrote:I think you are going about the voting the wrong way....
....................................
the problem lies in the fact that we won't "own" the infrastructure if we use leased-lines. not only will we have a recurring fee from the lease, but we'll be dependant on someone elses system. I kinda see their point, but from what i've learned, leased lines are relatively dependable and isolated from the rest of the telco switching and thereby not affected by hi-volume telephone traffic. i was told by our regional telco rep that pretty much the only things that could take down the leased line service are physical breaks in the line or if the switching hub blew up which is basically a physical break in the line.

Birken Vogt · Post by **Birken Vogt** » Sat Jan 28, 2006 10:53 am

I second all that. It is hard enough to get the telco techs to fix POTS service let alone anything out of the ordinary. We have DID lines into the paging system. Every time it rains some of them crap out. Dumb techs will go up there expecting to find dialtone. And they never, ever find the darn problem regarding water in the line. It has been that way for years.

The city has leased DC continuous lines from their maintenance yard, offices, etc that go up to their lowband site on a mountain. Same deal there. Those lines are constantly crapping out and we spend days and run up horrendous charges trying to track down the trouble only to find it is in the telco (like always). Last time they called regarding it we told them it would be cheaper for them to battle it out with the telco themselves rather than us charging $65/hr plus service call plus mileage to do it for them. Or else they can sign onto our own radio system and pay us to maintain it instead.

Not a bad deal when they are paying $400 plus per month for each of those leased lines IIRC

I always say the most reliable link is a copper loop but the darn telco seems to be making that into a falsehood these days.

Birken

kb4mdz · Post by **kb4mdz** » Sat Jan 28, 2006 12:08 pm

Hmmm, how much time (read $$) have they spent for this, when if they converted over to tone control on each end, they'd at the very least, have more forgiving circuits?

Course, you could always send telco a bill for your time when it is their fault; I have had telco techs 'threaten' me with that if they 'find' the problem is not theirs.... and as far as the customer, my view is that they depend on the radio tech to know the system, enough technical details to talk telco's language (ugga, ugggah, grunt, grunt, uhhm, how come me no get dialtone?)

Damned if you do, damned if you don't...
Chuk

Birken Vogt wrote: ...........................
The city has leased DC continuous lines from their maintenance yard, offices, etc that go up to their lowband site on a mountain. Same deal there. Those lines are constantly crapping out and we spend days and run up horrendous charges trying to track down the trouble only to find it is in the telco (like always). Last time they called regarding it we told them it would be cheaper for them to battle it out with the telco themselves rather than us charging $65/hr plus service call plus mileage to do it for them. Or else they can sign onto our own radio system and pay us to maintain it instead. Not a bad deal when they are paying $400 plus per month for each of those leased lines IIRC
Birken

Dan562 · Post by **Dan562** » Sat Jan 28, 2006 2:16 pm

In all due respect XMO is correct with his assumption of using a roofing filter on a co-located site with the T1786B Spectra-Tac Comparator, which incidently was Obsoleted Status 05 or No Longer Available as of December, 2005 being sold as a brand new unit through the /\/\otorola factory so this is a moot point.

Since eboe has specified the /\/\otorola Q2981A Digitac Analog Comparator with Option C175AGSP Transmitter TRC Control. This Digitac configuration would provide for multiple (8 to be exact) inputs from MTR2000 Satellite Receiver sites and the MTR2000 Base Station Repeater with Option C269 Spectra-Tac Wire Line Encoder. Eboe has decided to "run all the telco lines down to a centrally located building owned by us where the comparator" would be located. Then all that would be required is a 4 Wire Telco circuit to carry the repeater's recovered analog audio down to the Digitac comparator and the TRC with the transmit analog audio back up to the repeater. There's no need for a seperate MTR2000 Satellite Receiver co-located with the MTR2000 Base Station Repeater.

Since XMO has stated the following: "BTW, the MTR2000 cannot do fall-back in-cabinet repeat. The thieves at Motorola have decided that feature belongs in their "high tier" product line [i.e. Quantar]." There's an alternative method around this problem and this would be to order a second identical MTR2000 Base Station Repeater with the C269 Option, a 46" or 60" cabinet Option, (2) CLN1206A AUX I/O Option (Wildcard) one for each repeater station, (2) C540 Option, (1) Antenna Relay Option, (1) CLN1204A 4 Wire WL Euro Board (set for High Impedance) only required for one station when paralleling 600 Ohm Wire Lines, (1) CHN6130A Support Brackets (for mounting second station) and (1) CLN8185A Panel and Hardware (Telco Demarc Block, Mounting Panel & Hardware).

Rack up both stations and duplexers, leaving plenty of "air-flow" between the two units and configure them for the Main/Standby mode. You'll also have to Script the Wildcards for this application unless the factory has an orderable option. The antenna would switch the single Heliax feedline between the Main and Standby stations but you would be required to build two coaxial RF cables with "N" connectors to connect to the N.O. and N.C. relay ports and the common antenna port on each duplexer.

All I can state is the Telco T1 Lines are unbelieveably reliable when they are correctly implemented by the Telco provider. Most large Public Safety systems that are staged and tested in /\/\otorola's CCSi Bay in Schaumburg always are configured using this means of transport between the remote sites and the main location. As an alternative there are some systems using the newer broadband /\/\otorola Canopy product. Since /\/\otorola discontinued manufacturing their own Microwave (Point tu Point) product line, then you're required to purchase an OEM Microwave product which within a year or so would pay for itself and you would own the Infrastructure equipment.

spareparts · Post by **spareparts** » Sat Jan 28, 2006 2:24 pm

eboe wrote:you know what? i agree with you! i don't want to do it this way either, but it seems like every time i recommend the right way to do something, i'm asked for a different way or a cheaper way. I'd like to use MTR receivers, telco leased-lines, digi-tac comparator and call it a day.

RTNA's are for the most part reliable. HOWEVER - Be prepared for a bit of sticker shock when you see the monthly charges.

The other issue is can your TX site provide clean continuos pairs from the Verizon entry point to the roof? I just went through this with 2 different PS agencies on my site. I had a 4 wire RTNA that ping-ponged through 8 floors of IDF in a 6 story building. The other was a straight short from the MDF to the machine room up top. The straight shot was noisier then the long route.

If you go the leased-line route, make sure you get the circuit id for each and get the customer service record (CSR) for your telco account. Some of your circuits are likely to be inter exchange. The CSR will break out the charge details for you.

PS - e-mail me for the local special circuit people for Verizon

Martin